Water-going vessels are steered in any of a variety of ways. One way--commonly used on seagoing vessels and on larger pleasure craft--is to have one, two or more "screws" or propellers turned by shafts, the orientation(s) of which remain unchanged with respect to the vessel hull. Steering is by a separate rudder.
Another way commonly used with smaller pleasure craft is to pivot all or a part of the propulsion system so that the rotational axis of the propeller moves with respect to the vessel hull and its long axis. On so-called inboard-outboard drives, only a portion of the propeller drive train pivots. However, on boats driven by outboard engines, the entire engine (but for its stern mounting bracket and the like) are pivoted on the transom of the boat.
Smaller outboard engines are steered by an operator sitting at the rearmost seat and grasping the engine handle. Such handle not only pivots the engine about a generally vertical axis, it usually includes a twist-type throttle control. Thus, the operator controls vessel speed and direction with one hand.
But for larger outboard engines, hand steering in that manner is impractical. For one thing, the engine is simply too heavy to steer with one hand. And boats large enough to accept such an engine usually have steering and throttle controls at a forward seat location. The operator faces directly forward as when driving an automobile.
Larger outboard engines are often steered using some type of "force-multiplying" mechanism such as a steering wheel and control cable, the latter as made by Morse Controls and others. Or steering may be by hydraulic cylinder. In a common arrangement, the cylinder body is mounted in a fixed location and a cylinder rod is coupled to the engine tiller bar by a steering link. In another arrangement, the rods are at a fixed location and the cylinder body is coupled to the tiller bar for bar movement.
Apparatus for boat steering are shown in U.S. Pat. No. 2,787,235 (Schroeder); U.S. Pat. No. 4,773,882 (Rump); U.S. Pat. No. 4,836,812 (Griffiths); U.S. Pat. No. 5,340,341 (Yoshimura) and, no doubt, others. In the arrangement disclosed in the Griffiths patent, the center bracket on which the steering cylinder is rigidly mounted is, itself, rigidly attached to the steering arm of the primary engine.
The outer bracket to which the rods of the steering cylinder is attached is described as "stationary." A reason why such bracket may be so described is that pivoting the engine around its tilt tube (thereby raising the engine propeller) seemingly runs a high risk of badly damaging the outer bracket and/or the hydraulic cylinder. This is so since as the engine is so pivoted, the steering cylinder and related hardware are urged downward toward (and perhaps forcefully against) the boat transom.
The arrangements shown in the Schroeder and Yoshimura patents seemingly avoid the matter of possible cylinder damage during engine pivoting by locating the cylinder laterally to one side of the boat long axis. While this places the cylinder "out of the way," it complicates the mechanical linkages and results in a less-attractive installation which occupies more space than, in view of the invention, is necessary.
The assembly disclosed in the Rump patent uses a cylinder pivotably pinned to the tiller arm of an outboard engine. While such cylinder is directly in front of the engine, it is spaced well forward of such engine. Such assembly exhibits the same deficiency as the system of the Griffiths patent in that the cylinder is subject to damage when it is urged downward toward (and perhaps against) the boat transom.
The prior art, as represented by the above-noted patents, does not suggest a way to "closely-couple" a cylinder to an outboard engine and yet permit parts of such engine, e.g., the engine stern bracket, to "clear" the cylinder when the engine is tilted upward. And such prior art steering cylinders appear to be conventionally constructed and do not take advantage of the innovative features presented by the invention. An improved steering cylinder which addresses these disadvantages would be an important advance in the art.